Exchange 2003 OWA on a different port

I have exchange 2003.
I have a single public IP.
I use an ssl products that works over https:// port 443
I want to enable owa but with the single public IP I have, the port 443 is being redirect to an ssl applicance so owa will not work.
On my firewall I created a redirect of port 9443 to point to the exchange server.
When I am out of the office and enter http://mail.mydomain.com/exchange
I get the standard website certificate error (I do not have a trusted SSL cert installed), and I click "Continue to this webiste"
But the next screen I get is " The webpage cannot be found"
Why?
Thanks.

Does your router allow mapping of a different external port to an internal port?
If so port forward port 9443 external to 443 internal and the SBS IP. Then when connecting you have to specify the port as it will default to 443, such as:
https://mail.mydomain.com/exchange:9443

Please understand that if you change the default port of OWA from 443 you WILL break other SBS services and will be unable to use the SBS wizards to fix any future problems which may occur.

It is HIGHLY suggested that you do NOT change the port, but rather get a secondary external IP address if necessary. This will cause you significantly less headache and cost in the longrun. In fact, it may be a good idea to just use a separate ISP so you have built-in failover.